Considering the weight of shape detection roll and the strip tension, using a sine wave or a spline curve to virtual zero deviation of each channel, the dynamic zero compensation model was established based on the cut-off point method for deflection changes of the shape detection roll. For offline zero deviation by the shape detection roll's mass, the virtual sine cut-off point method was designed to compensate the offline zero deviation. For the online zero deviation by the dynamic high tension, the zero deviation was fitted by the spline curve to do it. Zero deviation fitting curve was subtracted from the measured curves, then more stable radial pressure value or the shape value can be obtained. In the application process, the recursive smoothing method can be used to make it more reliable for reflecting the actual shape condition of online strip. The measured datum show that the original waveform AD zero deviations of each channel reduces from 600 to within 50 after compensation, and the radial pressure decreases from 130N to 10N. So the zero compensation method has a great significance to improve the shape detection accuracy and shape close-loop control accuracy.